A data storage system, such as a disc drive, includes a base and a top cover that houses a variety of internal components. Example internal components include one or more data storage discs, a spindle motor and a spindle hub. The disc(s) are mounted to the spindle hub and the spindle motor drives the spindle hub which rotates the disc(s). A disc drive also includes external components. An example external component includes a printed circuit board assembly (PCBA). The PCBA is attached to an outer surface of the base.
Acoustic noise can be generated from the rotation of the spindle motor and the attached disc(s). Acoustic noise can also be generated from the actuator assembly that supports read/write heads which read and write data to the storage disc(s). A base and top cover house internal components of the disc drive and can amplify the sources of acoustic noise discussed above. More specifically, the base and top cover can substantially add to acoustic noise due to their resonance characteristics.
Independent of acoustic noise, mechanical resonance associated with components of the disk drive, such as operation of the actuator assembly, can result in read/write errors due to track misregistration. Disc drives with high track densities are particularly prone to track misregistration errors that can arise from excessive mechanical resonances. To alleviate vibration and acoustic noise as well as to provide dampening of mechanical resonances, a layer of damping material can be secured to the outer surface of the base between the PCBA, and the base.
The PCBA is used to compress the damping material against the base so that the damping material can perform its acoustic damping functions. Typically, screws are used to secure the PCBA to the base. The compression of the damping material forms a constrained layer that dissipates acoustic energy and mechanical vibration emitted by the disc drive. Additionally, the damping material acts to electrically insulate the PCBA from the drive housing.
When the PCBA is secured to the base, the pressure that the damping material applies to the PCBA in response to the compression again the base causes the PCBA to deflect outwardly away from the drive housing. With a sufficient amount of deflection, the disc drive can no longer comply with established dimensional form factor. In some instances, the deflection of the PCBA can be great enough that when the disc drive is installed in the designated computing device, damage to the disc drive occurs by contact of the disc drive with the internal components of the computing device.